The reaction of an organic halide with an organometallic compound in which the metal and the halogen atoms exchange laces is known as the halogen-metal interconversion reaction. Numerous studies have established the fact that the halogen-lithium interconversion is a general and widely applicable reaction. Many organic halides do not react satisfactorily with metallic lithium to form RLi compounds or with metallic magnesium to form Grignard reagents. However, the desired organolithium compound often can be obtained by a halogen-metal Interconversion reaction. The halogen-metal interconversion greatly extends the utility of organolithium and Grignard-type reactions.